contrib catalogs
This might seem like a silly question, but what are the implications of
PostgreSQL allowing developers to create custom catalogs?
For example, PostgreSQL currently uses the pg_catalog schema to store
system catalogs / relations / functions / etc. Has thought gone into
extending the scope to allow contrib modules to create their own
catalogs (ie. a PostGIS catalog, cube, tsearch2, etc.)?
The largest advantage I see is significantly easier upgrades. Having
contrib tables/functions flagged as a catalog, pg_dump won't include
them in a dump - restoring into an upgraded database becomes painless.
Cheers,
Kevin
Kevin Neufeld <kneufeld@refractions.net> writes:
This might seem like a silly question, but what are the implications of
PostgreSQL allowing developers to create custom catalogs?
For example, PostgreSQL currently uses the pg_catalog schema to store
system catalogs / relations / functions / etc. Has thought gone into
extending the scope to allow contrib modules to create their own
catalogs (ie. a PostGIS catalog, cube, tsearch2, etc.)?
A superuser can create whatever he wants in pg_catalog. Whether this
is a good idea or will behave smoothly is a topic that has not been
thought about, to my knowledge.
regards, tom lane
Really? I didn't know that ... guess I never tried. I'll have to do
some experimenting! Thanx Tom.
-- Kevin
Tom Lane wrote:
Show quoted text
Kevin Neufeld <kneufeld@refractions.net> writes:
This might seem like a silly question, but what are the implications of
PostgreSQL allowing developers to create custom catalogs?For example, PostgreSQL currently uses the pg_catalog schema to store
system catalogs / relations / functions / etc. Has thought gone into
extending the scope to allow contrib modules to create their own
catalogs (ie. a PostGIS catalog, cube, tsearch2, etc.)?A superuser can create whatever he wants in pg_catalog. Whether this
is a good idea or will behave smoothly is a topic that has not been
thought about, to my knowledge.regards, tom lane
Tom Lane wrote:
A superuser can create whatever he wants in pg_catalog. Whether this
is a good idea or will behave smoothly is a topic that has not been
thought about, to my knowledge.regards, tom lane
Sorry, Tom. I think you are mistaken. In my 8.3 instance, system
catalog modifications are not allowed.
/opt/pgsql83/bin/psql -p 5432 -U postgres postgres
Welcome to psql 8.3.3, the PostgreSQL interactive terminal.
Type: \copyright for distribution terms
\h for help with SQL commands
\? for help with psql commands
\g or terminate with semicolon to execute query
\q to quit
postgres=# \du
List of roles
Role name | Superuser | Create role | Create DB | Connections | Member of
-----------+-----------+-------------+-----------+-------------+-----------
postgres | yes | yes | yes | no limit | {}
postgres=# CREATE TABLE pg_catalog.test (id integer);
ERROR: permission denied to create "pg_catalog.test"
DETAIL: System catalog modifications are currently disallowed.
It would be interesting to test a contrib module install in pg_catalog
though.
Cheers,
-- Kevin
Kevin Neufeld <kneufeld@refractions.net> writes:
Tom Lane wrote:
A superuser can create whatever he wants in pg_catalog. Whether this
is a good idea or will behave smoothly is a topic that has not been
thought about, to my knowledge.
Sorry, Tom. I think you are mistaken. In my 8.3 instance, system
catalog modifications are not allowed.
Hm, I had forgotten that the allow_system_table_mods filter extends to
anything at all in pg_catalog. But you could easily enable that setting
in a test database and then see what happens.
regards, tom lane
Thanx for tip, Tom. I'll definitely give that a try in my spare time.
Cheers,
Kevin
Tom Lane wrote:
Show quoted text
Kevin Neufeld <kneufeld@refractions.net> writes:
Tom Lane wrote:
A superuser can create whatever he wants in pg_catalog. Whether this
is a good idea or will behave smoothly is a topic that has not been
thought about, to my knowledge.Sorry, Tom. I think you are mistaken. In my 8.3 instance, system
catalog modifications are not allowed.Hm, I had forgotten that the allow_system_table_mods filter extends to
anything at all in pg_catalog. But you could easily enable that setting
in a test database and then see what happens.regards, tom lane